This invention relates to a system and method for lifting trees, shrubs, and other plants from the ground for transplanting and more particularly, to a system and method for manually lifting plants with root balls attached to them for transplanting.
Digging and transplanting field-grown trees and shrubs is an important part of the nursery and landscaping business. Trees and shrubs which are grown in the nursery or found growing wild are generally transplanted to another location using either the bare root technique or the balled and burlapped ("B&B") technique. This invention relates to transplanting using the B&B technique.
In bare root transplanting, the root system of the plant to be transplanted is isolated by digging around the plant with a hand spade or the like. The plant is then removed from the ground and the soil is removed from the root system. The plant with its bare root system may then be transplanted. The bare root technique is generally appropriate only for small, dormant deciduous tress and shrubs up to 6 feet tall or small, dormant evergreens up to 1 foot tall. While this technique has the advantage of producing specimens for transplanting that are relatively light and easy to handle, it is generally not an appropriate technique for many of the larger trees and shrubs that a nurseryman or landscaper would want to transplant.
Plants of relatively large size with a significantly developed root system are generally transplanted along with a root ball made up of the roots of the plant extending for some distance from the base of the trunk and the soil surrounding those roots. For handling after the plant is dug, the root ball is generally wrapped in burlap or other similar material. Thus this method of digging and transplanting trees and shrubs is referred to as the balled and burlapped method, or "B&B" transplanting.
To transplant a tree or shrub using the B&B technique, the first step is to determine the size of root ball desired. The appropriate size of the root ball will vary with the variety of plant being transplanted and the size of the specimen involved. A general rule of thumb is that the root ball should be about 10 times the diameter of the trunk, measured just above the basal flare. Once the appropriate size of the root ball has been determined, the outline of the desired root ball can be laid out on the ground, and the root ball can then be dug following the outline. Depending on the size of the root ball and the depth desired, the root ball may be dug using a garden spade or various mechanical devices well known in the art.
A root ball for a relatively small tree or shrub may be prepared using a garden spade. The spade is used to cut the root ball free of the surrounding soil, as follows. The blade of the spade is driven into the ground along the outline of the root ball, angling the handle of the spade away from the plant at about 20 degrees from the vertical. The handle of the spade is then pried down and away from the plant slightly each time the spade is fully inserted into the soil to gently break the root ball free. Any roots which cross the cut line, down to the depth of penetration of the spade, are severed and a clear line of separation is established in the soil.
Once the root ball has been cut as described above, it may be lifted out of the ground, provided that the root ball is not too large and not too many uncut roots remain. For relatively small plants, it is possible to pry the root ball out of the ground with a spade. A root ball which is too heavy or bound by too many roots to yield to one person prying upward with a spade will sometimes yield to two or more people prying or pulling simultaneously.
In the case of a root ball that is too large to pry out of ground with a spade, the tree with its root ball weighing up to 500 pounds may sometimes be manually lifted to ground level as follows. A trench surrounding the root ball is excavated. Wrapping material such as burlap is put in place around the root ball after a trench has been excavated around the root ball, but before the root ball has actually been moved. Two or more people are then generally required to lift the root ball using the following procedure. One person shovels soil into the hole under the root ball, while an assistant, using the trunk of the tree or shrub as a lever, tilts the root ball from side to side. As the hole is filled under the root ball, the root ball will gradually "walk" its way up to the surface. Once at the level of the surrounding ground, the tree or shrub with its wrapped root ball may be moved. While suitable for some purposes, this method requires more than one person and is generally time consuming and cumbersome.
Alternatively, a trench around the tree or shrub may be excavated as described above and the root ball wrapped. A ramp is then dug from ground level to the base of the root ball. A two-wheeled hand truck (sometimes called a nursery truck) may then be pushed down the ramp, and the root ball placed on the hand truck. The hand truck may then be pulled back up the ramp to ground level. While this does allow a single worker to dig and lift a larger plant by hand, it requires arduous and time consuming excavation around the tree and wrapping the root ball while it is still in place in the ground.
In the alternative, to raise such large root balls, mechanically powered lifting devices, such as tractor mounted lifts and slings may be employed. Again, it is generally desirable to excavate a trench around the root ball and to wrap the root ball in burlap or other suitable material before handling. This requires additional time and effort in preparing the root ball, and generally results in the area surrounding the plant being substantially disturbed. Use of the power lifting equipment also requires that the site be accessible to the equipment, which is generally relatively heavy and large.
Certain other mechanical devices exist to dig, enclose and lift a large tree or shrub. In one such device, two or more broad blades are mounted on a power digger. The blades are positioned around the outline of the root ball to be dug with the leading edge of each blade at a suitable downward angle. The blades are then driven downward into the ground so that they meet under the plant and essentially enclose the root ball within the blades. The blades may be mechanically interlocked to strengthen the rigid container formed when they are in place under the root ball. The root ball and plant may then be lifted by power supplied by, for example, tractor mounted hydraulic equipment lifting the blades directly up.
Another type of mechanical digger/lifter is known in the art as a "U-blade" digger. In this device, a single blade in the shape of a "U" is mounted on a tractor or similar device. The blade is positioned so that the front of the blade is pointed down into the ground just outside the outline of the root ball to be dug. The blade is then driven down into the ground and simultaneously rotated under the plant so that it essentially scoops the root ball into the "U" of the blade. It may then be lifted out of the ground. However, because of the tensile strength of the roots and their holding power in the ground, it is advisable to at least partially cut the root ball free with a hand spade as described above before digging and lifting with a "U-blade" power digger.
Such diggers are available in models that may handle root balls up to 60 inches in diameter. They do, however, have a tendency to encounter a number of roots simultaneously as the broad front of the blade moves slowly through the ground, and to push those roots through the dirt rather than cut them cleanly. This requires significant power that may stall the digger. It may also lead to greater root damage than a device which cleanly cuts the roots.
These diggers, and indeed all of the mechanical slings and diggers, require power equipment to operate and are generally associated with a tractor, fork lift or other vehicle that may have difficulty accessing remote locations and steep or soggy terrain. It may not be possible to operate these vehicles in crowded locations with many trees or limited access. They may do significant damage to surrounding plants and other environmental aspects of the area around the trees or shrubs to be transplanted. The power equipment has attendant expense, maintenance, and safety considerations avoided by the manual lifting system of this invention. The blades used for digging and lifting may also require a heavy and stable base or other supporting structure. Generally, they also substantially enclose the root ball as it is being dug and lifted, making grooming of the root ball impractical.